class Fish{
    int weight;
}
class Lake{
    Fish fish;
    void setFish(Fish s){
        fish = s;
    }
    void eat(int n){
        fish.weight = fish.weight + n;
    }
}
class FishandLake{
    public static void main(String[] args) {
        Fish niqiu = new Fish();
        System.out.println(niqiu.weight);//输出1
        Lake taihu  = new Lake();
        Lake yangchenghu = new Lake();
        Lake qinghu = new Lake();
        taihu.setFish(niqiu);
        taihu.eat(15);
        yangchenghu.setFish(niqiu);
        yangchenghu.eat(13);
        qinghu.setFish(niqiu);
        qinghu.eat(9);
        System.out.println(niqiu.weight);//输出2
        System.out.println(taihu.fish.weight);//输出3
        System.out.println(yangchenghu.fish.weight);
        System.out.println(qinghu.fish.weight);
    }
}